We just stayed at Hotel Caracciolo, as a matter of fact I write this as we wait tl check out. This hotel is between Termini Station (the main train station/ metro/bus) and another station, this makes movement within the city fairly easy. I would recommend taking the leonardo express from FCO to Termini station and then walking to the hotel, it really is that close (this should cost about 28 euro). The hotel is very small and almost all of the staff are extremely helpful and we were delighted with the smiles, the greeting, the travel/sightseeing/dining tips and jokes that we received during our stay from the majority of the staff.

However, there is no alarm clock in the room (at least ours), the bathroom smelled of sewer whenever the toilet was flushed, And I have yet to find an english channel, such as BBC America, yet they do have that in the lobby. Breakfast is also a little limited from an American standpoint, however they keep it well stocked and that is much appreciated.
Also they only person that truly annoyed me, and this is probably because I'm used to different types of service, was last night about 1am I was trying to call France from the room phone, and the dialing instructions given by the hotel was not working, I went out into the lobby and all the lights were out, the night worker was passed out in the breakfast room on a cot, he woke up to me walking into the lobby and asked what I wanted, I told him and his reply was, the office is closed, ask again in the morning. Maybe this is typical of a European hotel, I'm just used to having 24 hour guest services. So take that tidbit with a grain of salt.

As an additional tip, I recommend not getting the Hop on Hop off tour bus sold by the hotel, unless u were to do a single round trip. It's very slow, crowded at times, and this service, Ciao Roma, seems to have the fewest number of Hop on Hop off busses.This bus ticket runs about 31 euro for 48 hours and this tour bus stops by 6pm.
I would however recommend getting a metro pass (probably a week long one) which runs 18 euro (alternative a daily pass is available for 4 euro and will last till midnight of that day, the metro system is easy to understand here, it includes all metros, city busses and trams (not the leonardo express to FCO though). The metro stops running at 9pm most days which will leave you on the bus, this is quiet a bit more difficult to understand, always ask the drivers they are also very friendly though you can tell their need for punctual departure.

All in all this is a very good hotel for the price in Rome, I would recommend this to anyone who is looking for a nice base of operations to see the ruins and who will only be resting/crashing at this hotel. The day staff and night staff as stated above are for the most part very friendly, knowledgeable, talkative, and overall great representatives of Italy.